syzbot


INFO: task hung in do_renameat2 (4)

Status: upstream: reported on 2026/02/11 16:33
Reported-by: syzbot+e6abc33728184c9172d7@syzkaller.appspotmail.com
First crash: 2d15h, last: 2d15h
Similar bugs (6)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in do_renameat2 (2) ext4 1 C inconclusive error 278 41d 649d 0/29 upstream: reported C repro on 2024/05/06 01:51
linux-6.1 INFO: task hung in do_renameat2 (3) 1 1 137d 137d 0/3 auto-obsoleted due to no activity on 2026/01/07 13:07
linux-5.15 INFO: task hung in do_renameat2 origin:lts-only 1 C done 6 403d 641d 0/3 auto-obsoleted due to no activity on 2025/04/16 19:25
linux-6.1 INFO: task hung in do_renameat2 1 1 746d 746d 0/3 auto-obsoleted due to no activity on 2024/05/09 03:01
upstream INFO: task hung in do_renameat2 f2fs 1 2 892d 927d 0/29 auto-obsoleted due to no activity on 2023/12/04 15:30
linux-6.1 INFO: task hung in do_renameat2 (2) 1 1 640d 640d 0/3 auto-obsoleted due to no activity on 2024/08/22 17:29

Sample crash report:
INFO: task syz.0.797:6697 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.797       state:D stack:28688 pid:6697  ppid:4275   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5245 [inline]
 __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562
 schedule+0xb9/0x180 kernel/sched/core.c:6638
 rwsem_down_write_slowpath+0xc2e/0x1110 kernel/locking/rwsem.c:1189
 lock_rename include/linux/fs.h:-1 [inline]
 do_renameat2+0x435/0xce0 fs/namei.c:4974
 __do_sys_rename fs/namei.c:5081 [inline]
 __se_sys_rename fs/namei.c:5079 [inline]
 __x64_sys_rename+0x82/0x90 fs/namei.c:5079
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fbf4f79bf79
RSP: 002b:00007fbf50578028 EFLAGS: 00000246 ORIG_RAX: 0000000000000052
RAX: ffffffffffffffda RBX: 00007fbf4fa16090 RCX: 00007fbf4f79bf79
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000200000000580
RBP: 00007fbf4f8327e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fbf4fa16128 R14: 00007fbf4fa16090 R15: 00007ffd999f9dd8
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2dfb0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2e7d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513
2 locks held by getty/4027:
 #0: ffff88814d0e9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198
2 locks held by kworker/u4:8/4969:
4 locks held by syz.0.797/6669:
2 locks held by syz.0.797/6697:
 #0: ffff88801eb8c460 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
 #1: ffff888072bdb510 (&sb->s_type->i_mutex_key#24/1){+.+.}-{3:3}, at: lock_rename include/linux/fs.h:-1 [inline]
 #1: ffff888072bdb510 (&sb->s_type->i_mutex_key#24/1){+.+.}-{3:3}, at: do_renameat2+0x435/0xce0 fs/namei.c:4974
1 lock held by dhcpcd-run-hook/10236:

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xeee/0xf30 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 11 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: events_unbound nsim_dev_trap_report_work
RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
RIP: 0010:lockdep_hardirqs_on_prepare+0x418/0x770 kernel/locking/lockdep.c:4316
Code: 52 6f 00 48 ba 00 00 00 00 00 fc ff df eb 8c 48 c7 c7 a0 23 8c 8a e8 f7 9d c8 08 48 ba 00 00 00 00 00 fc ff df b8 ff ff ff ff <65> 0f c1 05 60 6c 9e 7e 83 f8 01 48 8b 5c 24 18 75 34 48 c7 44 24
RSP: 0018:ffffc90000107a00 EFLAGS: 00000086
RAX: 00000000ffffffff RBX: ffff88813fec4658 RCX: adfc0d9ca46b8b00
RDX: dffffc0000000000 RSI: ffffffff8a8c23a0 RDI: ffffffff8adf0d20
RBP: ffffc90000107aa8 R08: ffffffff90af532f R09: 1ffffffff215ea65
R10: dffffc0000000000 R11: fffffbfff215ea66 R12: ffff88813fec4720
R13: 0000000000000004 R14: 1ffff11027fd88cb R15: ffff88813fec4700
FS:  0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fec5cab5ff8 CR3: 00000000277d5000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 trace_hardirqs_on+0x34/0x40 kernel/trace/trace_preemptirq.c:49
 __local_bh_enable_ip+0x136/0x1c0 kernel/softirq.c:426
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 nsim_dev_trap_report drivers/net/netdevsim/dev.c:820 [inline]
 nsim_dev_trap_report_work+0x763/0xaf0 drivers/net/netdevsim/dev.c:851
 process_one_work+0x8a2/0x1160 kernel/workqueue.c:2292
 worker_thread+0xaa2/0x1270 kernel/workqueue.c:2439
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
vkms_vblank_simulate: vblank timer overrun

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/11 16:32 linux-6.1.y 8ce36b2849ef 75707236 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in do_renameat2
* Struck through repros no longer work on HEAD.